1. Field of the Invention
The present invention relates to a method of cutting metal and non-metal materials with a tool attached to a working machine (e.g., a milling machine, lathe, grinding machine, gear cutting machine, etc.) that generates a non-combustible gas atmosphere at and around the tip of a cutting tool.
2. Description of the Related Art
Conventional cutting tools are usually attached to the spindle of a working machine and are cooled by injection of cutting liquid (e.g., liquid coolant) from the nozzle of a working machine to the top of the tool. This reduces friction and lowers the temperature of the tool, thereby ensuring more effective cutting and longer tool life. In addition, the injection pressure of the liquid coolant also works to wash away cut chips from the cutting area.
However, this conventional cutting and cooling method also necessitates the disposal of the sludge produced as a by-product of the liquid coolant. Since the used liquid coolant is mixed in with the sludge, it is difficult to dispose of the waste liquid without polluting the environment.
Environmental concerns in the workplace and in the local and global community lend impetus to the drive for better, safer preservation efforts. Thus, waste disposal of the spent cutting liquid (e.g., liquid coolant) becomes complicated and almost impossible. Under these circumstances, devising a cutting method that does not use a liquid coolant with its resulting waste is greatly needed.
Another problem exists in conventional methods because the cutting liquid is customarily recycled and reused. As a result, the liquid may experience a rise in temperature over time, possibly causing thermal expansion in machine parts. Thermal expansion is a major cause of inaccurate machining.
To overcome the above problems, there is a "dry cut" method which blows low-temperature air on the cutting part without using liquid coolant. Although sludge disposal is no longer required with the "dry-cut" or air-blow method, oxidization is accelerated at the cutting point, which results in a poor quality of the machined surface. In addition, this air-blow method provides inferior cooling efficiency of the cutting part compared to the liquid coolant method, and the cutting part becomes worn more quickly. Consequently, as the cutting part wears, the accuracy of a machined surface becomes increasingly poor.
Furthermore, when cutting is carried out on any high-viscosity material such as aluminum, a built-up edge may form on the cutting part resulting in poor accuracy on the aluminum material along with a deterioration in tool efficiency. In addition, coil-shape aluminum chips are formed making the dry-cut method more difficult.